Channel nuclear pore complex subunits are required for transposon silencing in Drosophila

The nuclear pore complex (NPC) is the principal gateway between nucleus and cytoplasm that enables exchange of macromolecular cargo. Composed of multiple copies of similar to 30 different nucleoporins (Nups), the NPC acts as a selective portal, interacting with factors which individually license passage of specific cargo classes. Here we show that two Nups of the inner channel, Nup54 and Nup58, are essential for transposon silencing via the PIWI-interacting RNA (piRNA) pathway in the Drosophila ovary. In ovarian follicle cells, loss of Nup54 and Nup58 results in compromised piRNA biogenesis exclusively from the flamenco locus, whereas knockdowns of other NPC subunits have widespread consequences. This provides evidence that some Nups can acquire specialised roles in tissue-specific contexts. Our findings consolidate the idea that the NPC has functions beyond simply constituting a barrier to nuclear/cytoplasmic exchange as genomic loci subjected to strong selective pressure can exploit NPC subunits to facilitate their expression.

Automated summary

The nuclear pore complex (NPC) functions as a gateway between the nucleus and cytoplasm for exchange of macromolecular cargo. Specific nucleoporins within the NPC, such as Nup54 and Nup58, have essential roles in transposon silencing via the piRNA pathway in the Drosophila ovary, suggesting tissue-specific functions for certain NPC subunits. This study demonstrates that genomic loci under selective pressure can exploit NPC subunits to facilitate their expression, indicating additional functions beyond nuclear/cytoplasmic exchange for the NPC.